The Secret Reason Why Post-Its Are Yellow

Of the many items you’re likely to find in an office, the Post-It might just be the most ubiquitous. First rolled out in 1977 as the “Press ‘n Peel” bookmark, it wasn’t until two years later, in 1979, that the popular product got its current name and an office icon was born.

However, the means by which Post-Its got their famous color has been hotly debated over the years. Many people have attributed the Post-It’s iconic yellow hue to everything from yellow’s supposed calming effect to its ability to be seen from a distance. And though the Post-It’s design may be ingenious, the product’s creation—including its famous color—was little more than happenstance.

According to Dr. Geoff Nicholson, former Vice President of Technical Operations at 3M, Post-Its are yellow because that was the only color of paper available when 3M began crafting their prototype. When he and 3M engineers went looking for some paper to make their initial batch of Post-Its with, they asked the lab next door for scrap paper to work on. The only scraps on hand happened to be yellow.

“They had some scrap yellow paper—that’s why they were yellow,” he told The Januarist on Twitter. “When we went back and said, ‘hey guys, you got any more scrap yellow paper?’ they said, ‘you want any more, go buy it yourself,’ and that’s what we did, and that’s why they were yellow.”

Despite the incidental nature of its discovery, Post-It yellow quickly became well-known enough for 3M to trademark the hue, meaning you won’t be seeing any other Post-It-colored office supplies anytime soon. And while the accidental origin story behind the Post-It’s iconic color may be surprising to some, they’re not the only coincidental aspect of the Post-It’s creation. In fact, the very adhesive used to stick Post-Its together was created by accident, too.

Dr. Spencer Silver, a scientist for 3M, had initially attempted to make a super-strong adhesive, only to find his efforts failing time and time again. Fortunately, a colleague suggested that the weak adhesive Silver kept coming up with might have another application: affixing bookmarks without ripping a book’s pages.